Azo dye.



UNITED srarns rarnur OFFICE.

Patented May 21,1912.

AZO 1m 1,027,132. v Specification of Letters Patent. No Drawing. Application filed January 4, 1912.

To all whom it may concern:

Be it known that'we, MYRTIL KAHN and ANTON OssENBncK, doctors of philosophy, chemists, citizens of the German Empire residing at Elberfeld, Germany, have .invented new and useful Improvements in Azo Dye, of which the following is a specification.

We have found that new azo dyestuffs are obtained by combining the diazo compounds of ortho-aminophenol sulfonic acids with meta-aniinobenzidin (2. 4t. 4J-triaminodiphenyl). The coloring matters thus obtained which have probably the following formula: I

SO H

are after being dried and pulverized brown powders soluble in concentrated sulfuric acid generally with a red coloration; yielding upon reduction with stannous chlorid and hydrochloric acid an ortho-aminophenol sulfonic acid and which after being chromed are distinguished by their excellent fast-ness to potting.

.In order to illustrate the new process more fully the following example is gii'en,

the parts being by weight :The diazo compound obtained from 23.4 parts of 6- nitro 2 aminophenol 4 sulfonic acid is added to a solution of l9.9 parts of amino benzidin dissolved in'the necessary quantity of hydrochloric acid. The mixture is gently heated to form 30%09 C. rendered slightly alkaline by sodium carbonate and 2.4-5.4-tetra-aminosulfonic acid 'diphenyl. -They dye wool in brown shadesphenyl; dyeing Wool in brown'shades which Serial No. 669,425.

gradual addition I of the dye is thetfilsalted out, pressed and dried. It is after being dried and pulverized coloration; yielding upon reduction with stannousehlorid and hydrochloric acid 2.6- diamino 1 phenol 4.- sulfonic acid and 2.4.5.4-tetraaminodiphenyl. The shade produced with it-is after being chromed a dark brown fast to potting. Other orthoaminoa brown powder sold- 7 ble in concentrated sulfuric ac1d with a red phenolsulfonic acids 6. g. Q-aminophenollsulfonic acid, d-chloro-Z-aminophenol-S-sub' fonic acid can be used.

We claim:

' 1. The herein described new azo dyestuffs which are after being dried and pulverized brown powders soluble in concentrated sulfuric acid generally with a red coloration; yielding upon reduction with stannous chlorid and hydrochloric acid an orthoaminophenol sulfonic acid and 2.4-5.4- tetraaminodiphenyl; dyeing wool in brown shades which after being chromed are distinguished by their excellent fastness to potting, substantially as described.

2. The herein described new azo dyestufi" which is after being dried and pulverized a brown powder soluble in concentrated-sulfuric acid with a red coloration; yielding upon reduction with stannous chlorid and hydrochloric acid 2.G-diamino-l-phenol-t and 2.4.5.4! tetraaniinodi- 

